Field of the Invention
The present invention pertains to the art of dishwashers and, more particularly, to a dishwasher including a system for delivering washing fluid to at least one lower spray arm associated with a lower rack and multiple upper spray arms carried by an upper rack.
Description of the Related Art
In the art of dishwashers, it is known to provide multiple, vertically spaced spray arms within a single wash tub in order to enhance the spray patterns of washing fluid. For use with these various spray arm arrangements, many different types of fluid distribution systems have been developed to address different problems or to provide a dishwasher with specific functionality. For instance, in order to increase the distribution of washing fluid, it is known in the art to provide a dishwasher tub with a lower, rotatable spray arm mounted for rotation below a lower rack, an upper, rotatable spray arm mounted above an upper rack and an intermediate, rotatable spray arm provided below the upper rack. In such an arrangement, the intermediate spray arm is mounted to the upper rack for concurrent movement into and out of the tub of the dishwasher. To accommodate this movement, a fluid connection must be made to the intermediate spray arm upon retraction of the upper rack into the tub.
If the upper rack is vertically adjustable, additional provisions must be made to provide the necessary fluid connection when the upper rack is in each of the various vertical orientations. In general, this adjustability function is accomplished by fixedly mounting a valve and manifold assembly to the tub at the height of the upper rack, with the manifold including multiple ports which can be alternatively accessed to provide the requisite washing fluid flow to the intermediate spray arm.
As an additional consideration, it can be desirable to provide a flow control system to regulate the flow timing to each of the spray arms. For instance, based on water pressure or other reasons, it may not be feasible to provide flow to each of the spray arms simultaneously. If this is the case, separate and distinct fluid conduits and/or complicated valving may be employed in combination with a water diverter mechanism in order to selectively direct the washing fluid to the lower wash arm, the upper wash arm, the intermediate wash arm or certain combinations of the wash arms.
Simply stated, regardless of these known systems, there is still seen to exist a need to further modify the parameters and configuration of an overall washing system within a dishwasher to provide a spray flow and coverage that will enhance the overall cleaning operation being performed.